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In order to count this Earthcache as a find, you must complete the following tasks and email the answers to me.
1. Estimate the approximate distance across the lake. Based on the information given, what is likely to happen to this distance?
2. Make an educated guess as to where the natural outlet of Lake Kampeska used to be.
3. Based on what you see at the location, is there anything that can physically be done to reduce the hypereutrophication of the lake?
This Earthcache is located at City Park, along the shores of Lake Kampeska. This park offers camping facilities, picnic shelters, beach area, and boat launch. The park is well kept and has plenty of space for parking. Please observe park hours. Enjoy!
About 20 thousand years ago, the last series of glaciers made its way across North America like a pancake spreading on a griddle. The large amounts of snow falling on the center of the glacier caused it to squeeze outward in all directions and the edges to creep farther and farther over the land.
The ice sheet eventually moved southward from the northeast and covered present-day South Dakota. As this glacier was moving into the area, a massive highland forced it to split in two. The larger slice moved in southeasterly direction, while the smaller segment was pushed south and west through what is now the James River Valley. Slowly, the larger piece of the glacier climbed up the dividing highland and joined up with the smaller segment in a continuous frozen expanse that buried the land.
Geologists believe that the glacier piled up as much as 1600 feet of ice in the area. Because of the massive thickness of this ice sheet and its weight, the glacier acted like a bulldozer and left quite a mark on the land it traveled across. It scoured and scraped the land, leveled high places and filled in low areas, smoothed some surfaces and gouged others. The landscape was further altered by the sudden moving, stopping, retreating, and moving again. When the glacier moved, it marked the ground with rocks and gravel frozen in its base. Sharp-edged rocks cut long grooves in bedrock and fine silt and clay polished surfaces smooth in places like Beadle, Grant, and Marshall counties. When the glacier stalled or retreated, it left behind piles of sediments called moraines. A moraine is an accumulation of unconsolidated glacial debris, such as soil and rock. All of the hills, ridges, and knolls found in the area are examples of these moraines. The smaller moraines show where the glacier was simply stalled, while the larger moraines indicate where the glacier retreated.
The Coteau des Prairies highland is the largest example of a glacial moraine in the area. This enormous wedge-shaped plateau, with its point just over the North Dakota line and its base in northwestern Iowa, grew from the ancient highland that divided the glacier. When the eastern slice of the glacier climbed up the highland, it brought with it eroded rock debris that were embedded in the bottom of the glacier. The more the glacier advanced, the more ice and frozen sediment it piled onto the highland. For as long as the glacier crept forward, the highland, with its growing pile of glacial debris, acted like a wall being built layer upon layer. When the glacier finally retreated in its entirety (when the ice finally melted), all of the sediments that were once frozen into the glacier were left behind.
Glacial lakes were also created as the glacier retreated. As the glacier started to melt away, huge chunks of ice broke away from the main ice sheet and were left behind. As the ice chunks melted, the land around them slumped in and created large round holes that later filled with water. Some of these holes were filled in by glacial streams, which were formed by the steady trickle of melting ice. Other holes were filled when the melting glacier sent forth a massive flood, which in turn created the ancient Glacial Lake Agassiz. With the exception of Lake Agassiz, which no longer exists today, these are the glacial lakes that now dot the landscape. Over 120 of these glacial lakes (about two-thirds of the state’s total) can be found in northeastern South Dakota - Lake Kampeska included. It is these lakes that give the region its name.
Since the passage of the glaciers in the area, nothing else has so profoundly affected northeastern South Dakota, except man. In his article “Lakes in Peril,” Ried Holien explains how humans are negatively impacting the lives of glacial lakes. Holien states, “Mother Nature intended [glacial lakes] to prosper for centuries. But pollution and misuse have conspired to shorten their life span to a matter of decades.” Glacial lakes have always been meant to die, or to dry out. However, humans are causing them to die at a much quicker pace.
Holien describes in his article the process of eutrophication, the natural, biological enrichment process through which glacial lakes are meant to die. “When young, a glacial lake is clean, cold, and deep. It supports little life. Over time, plant and animal life grows. Organic waste and eroded soil get deposited, causing the lake to become shallow and warm. Marsh plants thrive in this nutrient rich water. Sedimentation and vegetation transform the lake into a slough, then eventually to solid earth.”
Eutrophication is a natural condition for many lakes. However, this condition is frequently a result of nutrient pollution, such as the release of liquid sewage waste, stormwater run-off, and run-off carrying excess fertilizers. Eutrophication generally promotes excessive plant growth and decay, favors certain weedy species over others, and may cause a severe reduction in water quality. In aquatic environments, this excessive growth of aquatic vegetation disrupts the normal functioning of the ecosystem and causes a lack of oxygen in the water--oxygen needed for fish to survive. When this happens, the water becomes cloudy and turns a shade of green, yellow, brown, or red.
The process of eutrophication of glacial lakes in northeastern South Dakota, Holien explains, is being accelerated by humans and killing the glacial lakes centuries before they are naturally meant to die. “Real estate development and agricultural plowing increase erosion; nitrates and phosphates, primarily from agricultural fertilizers and animal waste, promote the growth of blue-green algae and aquatic weeds.” Blue green algae and other aquatic weeds, which grow as a result of fertilizer and waste, release toxins (or poisons) that are harmful to people and frequently lead to the closure of recreational waters. On a more personal level, humans face economic issues with the dying of each glacial lake: “at stake are the tens of millions of dollars and thousands of jobs in the hunting, fishing, and boating and recreation industries, which depend on the glacial lakes.”
Holien’s article notes a recent government study that classified Lake Kampeska as being “hypereutrophic” or existing in a state of extreme biological degradation. If something is not done to stop this problem, the study warns that Lake Kampeska could become effectively useless within a number of years.
The loss of Lake Kampeska would be extremely detrimental to the Watertown community. Holien explains, “Kampeska has the most per acre recreational use and the highest property value of any South Dakota natural lake. Losing that $60 million dollar tax base could cripple the school system, and necessitate raising taxes on other systems.”
Economics aside, Lake Kampeska is also important in controlling flooding. “When lakes grow shallow, flood damage worsens. Lakes are natural flood control buffers. With their capacity diminished, floodwater flows elsewhere, like to populated areas.” Lake Kampeska used to be about forty feet deep, but is now only about twelve--and all because of human activity. In his article, Holien explains that the city of Watertown closed one of Lake Kampeska’s natural outlets in the 1940s in order to build an airport. By closing this outlet, the Big Sioux River was transformed into Kampeska’s entrance and exit. “Without this natural flow,” Holien explains, “river water slows, then deposits its suspended material. In the spring of 1994, the Big Sioux channel brought 400,000 tons of sediment into Kampeska, but carried out only 4000 tons.” Because Lake Kampeska is hypereutrophic, flooding occurs more often--even during periods of normal precipitation. This is because eutrophied lakes cannot accept the same water levels.
While people are driving their boats around the lake, tossing garbage into the lake, or washing their car in their driveway five miles away from the lake (soap contains phosphorous, which can produce 500 pounds of algae, which releases toxins), they do not realize that what they are doing is actually killing the lake. People never think of lakes in terms of life-span. Most just assume the lake will be there forever (or at least throughout their life time). All of the human activity on and around Lake Kampeska and all of the pollutants that end up in Lake Kampeska (and other glacial lakes) are taking years and years away from the life of the lake. If something is not done to slow the hypereutrophication process Lake Kampeska is currently experiencing, the Lake will be gone before we know it, and with it, money, jobs, and the fish and wildlife that once thrived in this area.
Resources:
Holien, Ried. “Lakes in Peril.” South Dakota Magazine November/December 1997: 8-13; 86-90. Print.
NOT A LOGGING REQUIREMENT: Feel free to post pictures of your group at the area or the area itself - I love looking at the pictures.
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